Symfony UX is a JavaScript ecosystem for Symfony. From 2.2.0 until 2.36.0 and 3.1.0, Symfony\UX\Autocomplete\Doctrine\EntitySearchUtil::addSearchClause() builds the LIKE expression used by the autocomplete endpoint by wrapping the client-supplied query in %...% without escaping SQL LIKE wildcards (%, _, \), allowing unauthenticated users to turn the public BaseEntityAutocompleteType endpoint into a broad matcher or blind boolean oracle against every column in default searchable_fields. This issue is fixed in versions 2.36.0 and 3.1.0.

Affected: Packagist: symfony/ux-autocomplete

### Description

`Symfony\UX\Autocomplete\Doctrine\EntitySearchUtil::addSearchClause()` builds the `LIKE` expression used by the autocomplete endpoint by wrapping the client-supplied query in `%...%` without escaping the SQL `LIKE` wildcards (`%`, `_`, `\`). The value is passed as a bound parameter, so this is not SQL injection, but a client can send `%` to match every row or use `_` as a single-character wildcard.

Because `searchable_fields` defaults to every property of the entity and the autocomplete endpoint is public by default (`BaseEntityAutocompleteType` ships with `security => false`), an unauthenticated user can turn the endpoint into a broad matcher or a blind boolean oracle against every column of the entity, including columns the application never intended to expose.

### Resolution

`EntitySearchUtil` now escapes `\`, `%`, and `_` in the user-supplied query with `addcslashes()` and appends an explicit `ESCAPE '\'` clause to the generated `LIKE` expression, so those characters are matched literally. The exact-match `words_query` `IN()` branch is unchanged.

The patch for this issue is available [here](https://github.com/symfony/ux/commit/725ab3d40689c91ff19ad2d01940a30007769214) for branch 2.x (and forward-ported to 3.x).

### Credits

Symfony would like to thank Pascal Cescon for reporting the issue and providing the fix.